In order to reduce the weight of the driven rotating body while ensuring the strength thereof, Patent Document 1 discloses a valve opening/closing timing control device that includes a driven rotating body that is configured with: a cylindrical outer circumferential member that is made of a lightweight aluminum-based material; and a cylindrical inner circumferential member that is made of an iron-based material having a higher strength than the aluminum-based material, the outer circumferential member and the inner circumferential member being integrated into one piece so as to have the same rotational axis.
This valve opening/closing timing control device is configured to control the rotation phase of the driven rotating body relative to the driving rotating body by supplying/discharging a pressurized fluid to/from an advancing chamber or a retarding chamber from the camshaft side via an advancing channel or a retarding channel.